While studies of cognitive development have become increasingly popular, much less attention has been devoted to the analysis of the child's motivational processes. Given the general one-sided emphasis on the study of cognitive variables, we know very little about the developmental course of a variety of motives, or how motivational hierarchies may change with age. A central theme throughout much of the proposed research concerns the development and interaction of two general motive systems--one involving the intrinsic motivation to master, to explore, to learn, and the other involving the need for external social approval or praise. The role of intrinsic mastery motivation, and what Robert White has termed "effectance motivation", in particular, has received little empirical attention. The proposed research will be directed toward an examination of the following six issues: (1) the nature of effectance motivation, i.e., is it best viewed as a unitary constuct or is a component model more appropriate. Given the paucity of empirical work in the area, a large portion of this research has and will continue to be directed toward the construction and refinement of adequate operational measures. (2) developmental differences in the components of effectance motivation we have isolated; (3) the relative strength of effectance motivation and need for approval in the child's motive hierarchy at different developmental levels; (4) the pleasure which children derive from cognitive challenge and mastery; (5) the role of curiosity within the effectance motive concept and it's relationship to learning and mastery; (6) educational implications of these two motive systems, namely the relative strength of effectance motivation and need for approval in the classroom.